In order to create desired surface features on a semiconductor wafer or other substrate, an ion beam of prescribed energy may be projected onto the surface of the substrate in a predetermined pattern to “etch” the desired features into the substrate. During this etching process, the substrate can be mechanically driven or “scanned” in a direction transverse to an ion beam projected onto the substrate by an ion source. For example, if an ion beam is projected along a horizontal plane toward a vertically-oriented substrate, the substrate may be scanned in a vertical direction and/or in a lateral direction perpendicular to the projected ion beam. Thus, the entire surface of the substrate can be exposed to the ion beam.
Etching a substrate with an ion beam creates residue in the form of sputtered atoms dislodged from the etched surface of the substrate and redeposited on another portion of the substrate. This residue can be detrimental to the quality of a finished substrate if not removed. In order to remove the residue, a substrate can be exposed to various “residue removal gases,” such as methanol, ethanol, or isopropanol before, during, and/or after etching of the substrate. Such residue removal gases may react with atoms sputtered from an etched surface of a substrate to form volatile molecules. These volatile molecules can then be evacuated using vacuum pumps or the like.
Conventionally, residue removal gases are introduced into a process chamber of an ion beam device through a “shower head” structure located adjacent a substrate that is being processed. In order to provide sufficient clearance for the substrate and for components of the ion beam apparatus, the shower head is typically positioned some distance away from the substrate. Thus, the presence of the shower head necessitates a process chamber significantly larger than would otherwise be necessary. Additionally, since the shower head is positioned a significant distance away from a substrate, the residue removal gases emitted by the shower head diffuse throughout much of the process chamber before drifting into contact with the substrate. Much of the residue removal gases are removed from the process chamber before reaching the surface of the substrate, resulting in inefficient and ineffective delivery of the residue removal gases.
With respect to these and other considerations the present improvements may be useful.